In the loading and unloading of a vehicle parked at a loading dock, it is important from a safety standpoint that the truck or trailer bed thereof be held in position against the bumpers which are mounted on the front wall of the dock and be restrained from accidental or inadvertent movement away the dock front wall. Heretofore the truck or trailer was held in place by either (a) wheels chocks wedged in front of the rear set of wheels; (b) anchor chain or cable having one end thereof secured to the dock and the other end releasably attached to the rear of the truck or trailer; or (c) complex and costly devices which are difficult to install and frequently require substantial modifications being made to the dock and/or the road way on which the truck or trailer is parked. The latter devices are incapable of effectively securing vehicles wherein the ICC bars thereof vary in height and location over a wide range.
Wheel chocks are the most commonly employed because of their simplicity of design; however, they are susceptible to becoming lost or stolen; are ineffective where the roadway surface is slippery due to ice, water or oil drippings; and the proper positioning of the chocks relative to the rear set of wheels is normally the responsibility of the vehicle driver and is dependent upon the diligence and care exercised by the driver.
Because of the awkwardness and time required to properly attach and detach the chain or cable to or from the parked vehicle, they are oftentime disregarded by the driver or dock personnel and the driver instead relies solely on the braking capability of the truck or trailer itself to maintain the vehicle in place against the dock bumpers.
Some of the prior vehicle restraints require troughs or ditches to be formed in the roadway or require recesses or pockets to be formed in the dock wall in order to accommodate various components of the particular restraint. Thus, the installation costs are inordinately high and require defacement of either the roadway or dock wall. In other instances, some prior vehicle restraints require elaborate controls and various power sources to actuate the restraints which add significantly to the complexity and costs of the restraint. In still other prior vehicle restraints, they are susceptible to malfunction due to certain of the components thereof being exposed and adversely affected by severe climatic conditions.